1. Technical Field
The present invention relates to a printing cylinder assembly for a printing machine in which a printing cylinder whose diameter is changeable is used to produce printed images that are different in their top-bottom length.
2. Background Art
A printing machine designed to print on a continuous sheet or web of paper, print images which are different in top-bottom length has been disclosed in JP 2004-74526 A.
Such printing machines are known as a sleeve cylinder exchangeable variable printer, in which a printing cylinder comprises a sleeve cylinder removably mounted to fit on the rotating shaft so that it can be fitted on, and be extracted from, the rotating shaft. Sleeve cylinders of different diameters are prepared for printing images of different top-bottom lengths and a sleeve cylinder is selected which is of a particular diameter that meet a particular top-bottom length of an image to be printed. Each of such sleeve cylinders is mounted on the rotating shaft to print on a continuous web of paper print images different in top-bottom length.
To enable a sleeve cylinder to be exchanged in the conventional printing cylinder assembly described above in which the sleeve cylinder is removably mounted to fit on the rotating shaft so that it can be fitted on and be extracted from the rotating shaft, it is necessary to couple the sleeve cylinder and the rotating shaft together so that the sleeve cylinder may not move axially or rotate around the rotating shaft but may be rotated integrally with the rotating shaft, and by releasing the coupling to decouple the sleeve cylinder from the rotating shaft so that the sleeve cylinder can be extracted from and be fitted on the rotating shaft.
Moreover, in order for the sleeve cylinders to be exchanged in a short period of operating time, it is desirable that coupling and decoupling of a sleeve cylinder and a rotating shaft as mentioned above be simply accomplished.
In view of problems as mentioned above, it is an object of the present invention to provide a printing cylinder assembly in which a sleeve cylinder can removably be mounted to fit on a rotating shaft so that it can be fitted on and be extracted from the rotating shaft and in which coupling and decoupling of the sleeve cylinder and the rotating shaft can simply be accomplished.